diff --git a/infer/src/nullsafe/ThirdPartyAnnotationInfo.ml b/infer/src/nullsafe/ThirdPartyAnnotationInfo.ml
index 4dbf9c443..806dcc50b 100644
--- a/infer/src/nullsafe/ThirdPartyAnnotationInfo.ml
+++ b/infer/src/nullsafe/ThirdPartyAnnotationInfo.ml
@@ -32,13 +32,20 @@ let bind_list_with_index ~init list ~f =
       Result.bind acc ~f:(fun acc -> f acc index elem) )
 
 
+let is_whitespace_or_comment line =
+  let stripped_line = String.strip line in
+  String.is_empty stripped_line || String.is_prefix stripped_line ~prefix:"//"
+
+
 let parse_line_and_add_to_storage signature_map ~filename ~line_index line =
   let open Result in
-  ThirdPartyMethod.parse line
-  >>= fun (signature, nullability) ->
-  Ok
-    ( Hashtbl.add signature_map signature {filename; line_number= line_index + 1; nullability} ;
-      signature_map )
+  if is_whitespace_or_comment line then Ok signature_map
+  else
+    ThirdPartyMethod.parse line
+    >>= fun (signature, nullability) ->
+    Ok
+      ( Hashtbl.add signature_map signature {filename; line_number= line_index + 1; nullability} ;
+        signature_map )
 
 
 let add_from_signature_file storage ~filename ~lines =
diff --git a/infer/src/unit/nullsafe/ThirdPartyAnnotationInfoTests.ml b/infer/src/unit/nullsafe/ThirdPartyAnnotationInfoTests.ml
index f846f142f..841488d67 100644
--- a/infer/src/unit/nullsafe/ThirdPartyAnnotationInfoTests.ml
+++ b/infer/src/unit/nullsafe/ThirdPartyAnnotationInfoTests.ml
@@ -91,6 +91,25 @@ let basic_find =
   assert_no_info storage {class_name= "a.A"; method_name= Method "foo"; param_types= ["b.B"; "c.C"]}
 
 
+let disregards_whitespace_lines_and_comments =
+  let open ThirdPartyMethod in
+  "disregards_comments"
+  >:: fun _ ->
+  let lines = [" "; "a.A#foo(b.B)"; ""; "// a.A#bar(b.B)"; "// Hello world"] in
+  (* Load some functions from the file *)
+  let storage =
+    add_from_annot_file_and_check_success ~filename:"test.sig"
+      (ThirdPartyAnnotationInfo.create_storage ())
+      ~lines
+  in
+  assert_has_nullability_info storage
+    {class_name= "a.A"; method_name= Method "foo"; param_types= ["b.B"]}
+    ~expected_nullability:{ret_nullability= Nonnull; param_nullability= [Nonnull]}
+    ~expected_file:"test.sig" ~expected_line:2 ;
+  (* Commented out signatures should be ignored *)
+  assert_no_info storage {class_name= "a.A"; method_name= Method "bar"; param_types= ["b.B"]}
+
+
 let overload_resolution =
   let open ThirdPartyMethod in
   "overload_resolution"
@@ -242,6 +261,7 @@ let test_is_third_party =
 let test =
   "ThirdPartyAnnotationInfoTests"
   >::: [ basic_find
+       ; disregards_whitespace_lines_and_comments
        ; overload_resolution
        ; can_add_several_files
        ; should_not_forgive_unparsable_strings